"Kue Putu" is a traditional Indonesian cake that is well-known to the students. Besides, the "Kue Putu" mold is made from cylinder-shaped bamboo culm and possesses the potency for learning geometry in a meaningful way. In addition, Indonesian Realistic Mathematics Education (IRME) is a mathematical learning strategy in which students study using context relevant to learners' life as beginning points. The article examines a mathematics learning design on the area and volume of cylinders using ethnomathematics context carried by traditional cake mold assisted by GeoGebra. This material is designed to help students understand the relationship between surface area and volume by examining the diameter and height of the cylinder. In developing the design, a research method, namely Design research, was applied. Following Design Research from the Gravemeijer model, we tested design research in terms of Hypothetical learning trajectory on area and volume of cylinders in the three phases, namely preliminary design, teaching experiment, and retrospective analysis. The study resulted in the theoretical design and practical instruments based on the method that contributes to instructional theory and supports student learning on the area and volume of the cylinder. Students show excellent reasoning on how increasing cylindrical radius gives a more significant effect than increasing its height. The student also construes the design of the cylinder that provides the most considerable volume by expanding its base or radius.